A bit of interesting trivia is that this plane was flown by James Bond, to Scaramang's island, in The Man With the Golden Gun. Scaramanga blew it up, while demonstrating a to James. James wasn't happy.
Also interesing is the Robinson Conversion, where they are installing Corvette V-8 engines in the Seabee. There is a recent replical of a Vietnam Seabee, that has gotten magazine coverage lately.http://www.v8seabee.com/status.asp

The build started with the 2-view line drawing, and an online build, that had pics which have proved priceless. I even found video yesterday, of that online build, completed and flying off water. That build was from a 1977 RCM plan. Sheer coincidence, a photo of the build was posted in the Public Photo section of AMA's last month mag. Also coincidence that I scaled to 51" span, the same as the RCM plan. The RCM plan is not scale. The online build I've been referencing had mods done to the plan, to make it more scale. Still, the tailboom was off-scale, so thanks to Dave Blum's 2-view line drawing, I got all the correct sections for the tailboom.http://hangaren.pointclark.net/rchangar/rcseebee.htmlhttp://www.flyingmodels.org/showtime/SeeBee_h.htm

As a scratch build, numerous hours were spent just in developing the plan, and cutting parts, many of them being light ply. For all practical intent and purpose, I started with a 2-view drawing, that had some critical outlines, but no parts drawn into it. For the most part, my basic parts structure resembles the modifed RCM plan build, that I listed above.

At this point, I have the combined main gear and tailwheel retract mechanism working from a single GWS Micro (like HS81) servo. Both the tilt-away tail wheel, and the main gear, all work together. I plan to get a retract servo, but the mechanism removes the strain from the servo in both up and down positions. In the down position, it has a locking knee. In the up position, a progressive helper spring setup can hold it up by itself, without assist from the servo. I need an updated pic.
Flats were filed onto all of the axle shafts and the gear retract shafts also, for positive lock of the set screws, and to hold all the relative positions of the components. Some of the mechanism will not be serviceable when complete, so it better not break. The indexing flats also make it easy to dissassemble and reassemble the mechanism, without spending time to position all the parts, as this is now done by the indexing flats. The main gear pivot shaft and the gear strut legs can easily be removed and reinstalled on this design. The struts are actually made from Dubro 1/8" axles, with longer shafts made for the struts, since the included axle shafts are not long enough to be used for struts. Fot the wheels, I simply used a collar with a bolt replacing the set screw, for an axle. Aluminum tubing can be placed over the bolt, and the wheel can be drilled a few thousandths larger than the tubing size, for a smooth axle surface. These struts also have indexing flats filed on them, so that they can easily be removed and reassembled, with no time spent on positioning the parts.

The first build pic below shows about 2 or 3 revisions to the retract mechanism, before the current one, which actually works well now. The second retract pic shows where the linkage connects to the tailwheel torque rod. Still to be designed, is a steerable tailwheel mechanism that will permit the tilt-away retraction. Only some full size Seabees have a steerable tailwheel, and the ones that don't are difficult to track straight on land, with just the rudder force.

The tail feathers were considerable work. They are build using spar construction, to simulate the "ribbed" aluminum sheet, used on the full size plane, once covered with iron-on covering. I plan to simulate these ribs in the wing too.

I'm planning on the blue and white sheme (pic of full-size plane).
Normally I'm not a fan of light blues, but I like it on on this plane, and have the colors in iron-on covering also.

Hi BILL that really looks like a Challange, Looking great so far, i think I would be afraid to fly it, With all the work and time that goes into a project like that, I will be following you build, take care, Chellie

Hi BILL that really looks like a Challange, Looking great so far, i think I would be afraid to fly it, With all the work and time that goes into a project like that, I will be following you build, take care, Chellie

I'm afraid to fly a lot of my stuff.
I usually maiden somewhere between 2 months and 2 years after a build.
Seaplanes, needing water for the real experience, provide yet another excuse.

PD1, I wasn't going to bother to continue posting this build, until I checked back there, and found out that there was actually interest in it. I think its better posted over here anyways. This forum here could use some new posts. Over there, if you're not part of the "expert" clique, they could care less about your posts, and in my case, even jump on you.
For some laughs PD1, why don't you copy my pics from here, and post them over there in my other Seabee thread, that I can no longer post in. I'd like to see if they bring up a "technicality" and say that it is not allowed.

On the Seabee, I've been experimenting with ideas for the steerable tailwheel. I fabricated the wheel caster mounting block, which attaches to the tailwheel torque rod, using a wheel collar embedded inside it to lock it to a flat spot filed on the torque rod. This part rotates about 90 deg to swing the wheel out of the water. Trying to decide how to make it steer now. So far, the easiest way seems to be a drag link driven by the water rudder, with ball sockets on either end. I wish I could use something that is more inconspicuous, but having the steering mechanism work with a retracting "swing away" tailwheel makes it more difficult.

The real "wrench thrower" is that the wheel should retract from any position in its steerable range. I have some other ideas, but I don't like the idea of having to have the rudder in the centered position, for retraction to work. There's no reason to have to make it like a nosewheel which retracts into a nosebay, where in that case, the wheel must be pointing straight ahead. I wan't to avoid that situation.

Your work is always amazing to watch. Can't wait to see more pictures of your progress on this one. I also can't imagine why anyone wouldn't think you're an "Expert". You have some of the finest detail work I've seen.

Bill, the full sized took care of the tailwheel off center, by spring loading the wheel ( to auto center) and the cables, to stretch a little.
If you can use something like a pull pull system, then the cables can "loosen" when the wheel assembly is rotated, with springs to keep a little tension on the cables.

Thanks Grasshopper. A lot of the "so called" rc experts hang out at that other place, in the scale forum there. Spend enough time there, and you'll get the drift. If you haven't been published, you're not part of the group. Even the contest they have now, has 2 categories, amatuer and professional. If you haven't been published, your automatically amatuer. I don't buy that, and would not enter under those terms.
Do enough building and you quickly realize that any common fool can design a balsa airplane. Converting it to a functional rc plane, with all the mechanisms, is the real challenge. Kindof like the Guillows conversions. One experienced builder recently said that he finally figured out why so many folks like Guillows conversions so much. Its because they are often NOT ideal for converting, which makes it a challenge.

Originally Posted by pd1

Bill, the full sized took care of the tailwheel off center, by spring loading the wheel ( to auto center) and the cables, to stretch a little.
If you can use something like a pull pull system, then the cables can "loosen" when the wheel assembly is rotated, with springs to keep a little tension on the cables.

That's pretty much what I've come down to also. I just couldn't stomach the large drag link idea I had. Actually, what I'm thinking now is just a pull cable setup, without even needing "pull-pull", if I use a spring to force the wheel to one direction as a default.

The pull-pull would need springs to loosen when the wheel swings to retract, as you described. I still may end up doing that, but more likely with a single cable and a spring that forces the wheel to one direction, the cable springs would not be needed, since the wheel would simply turn a bit, when it swings to retract.

I still have another thought, which is a take-off of your idea. This would be to use spring wire attached to the steering shaft, to in essence make a control horn. For example, the wire could go through a hole in the shaft, and attach to the cables at the ends of the spring wire. The spring wire would be able to bend a bit, to take care of the cable length change, as the wheel swings to retract.

The one thing that I will probably do now, regardless of what variation of cable method used, is to drive the wheel from the water rudder. Using kevlar pull-pull cable, the setup will be like a "drag link". The cable/s will attach to arm/s coming off the top of the water rudder, at its hingeline. This works well, as it will steer the wheel in the correct direction along with the water rudder. I've used this "drag link" take off method before, to steer tailwheels from the rudder. Its useful where you want to mount the tailwheel a bit forward of the rudder, which can't use the simple method of inserting the steering arm into the rudder, since the steering axis is not in-line with the rudder hingeline. Pretty much the same idea here, except for that the rudder is a water rudder.

The Wheel Caster
I have the wheel caster parts made now. The main pivot block is a section of a nylon wing hold-down block. Embedded into it, is a wheel collar. The wheel collar set screw locks onto a flat spot that is filed onto the torque rod that it mounts on. The flat spot is about 1mm back from the end of the torque rod, so it can't slip off. If you look closeley at the pic, the bottom of this long set screw can be seen in the bottom of the nylon block. It seems to be working well.

The actual mounting caster is a part from an old record player. The steel that the dang thing is made of, is so hard that it will not drill easily. I drilled a hole in one side for the wheel axle, but the other side broke, when I was drilling the hole it it. What I did was to slip oval aluminum tubing over the caster arms, crimped it flat with pliers, and then drilled through the alum for the axle holes, while going through the one good hole that I managed to drill into the wheel caster arm.

Once this part is inserted into the pivot block, I will then press on a threaded linkage shaft onto the wheel caster arm, from the opposite side of the pivot block. Now I will be able to use nuts to attach whatever type of steering arm that I decide to use. For example, a servo control horn is shown in the picture.
These parts are resting on a picture of the tailwheel caster of a full-sized Seabee.

Bill, If the tailwheel pivot starts to drive you nuts, you can allways make a well rear of the tailwheel and retract the wheel rearward.
I don't think anyone would ever know the difference, and it should be a lot easier.

Looking at your pictures again reminds me of the first Sea Bee I flew.
The factory gear mechanism is almost identical to yours, just the actuator was ahead of the tranverse tube, and it was under the floor.

You still came up with a system that will do the same, without a hundred engineers taking months to design.

Good going.

The Sea Bee looks great taxiing out of the water and up the ramp.
Yours should look equally as good.

Thanks PD1. I bet they did make quite a project out of the original Seabee tailwheel design. As far as I know, it was a modification after the original design.

I know one thing, that it probably did not steer worth crap by just using the air rudder, without a steerable tailwheel. I bent some caster angle on my wheel fork, but could not bend that much, as the steel that the part was made of is diamond hardness. I didn't want to break it. When I mounted it on the plane, the angle is only a degree or so, since the plane sits down so low at the rear. It eliminated most of the caster angle that I bent into it. If I push the plane, and try to use my hand to simulate side force generated by moving the air rudder, then it would probably need a football field to turn around. It will try to turn the caster, but slooowly. Definitely want this steerable tailwheel.

After you told me about the cable operation, I looked at the pic that I printed off of the web, and could barely see the cable on one side. Now it makes more sense. If the cables exit near the mounting shaft location, then the length change will not be that severe. I may do that, as they will be less conspicous, than if they come off of the water rudder. I could run them inside nylon pushrod sheathing, and route the sheathing up high enough in the fuse to be well above the water line, thus no leakage into the plane. My setup may turn out to be very much like the full-scale plane's.

Originally Posted by pd1

Bill, If the tailwheel pivot starts to drive you nuts, you can allways make a well rear of the tailwheel and retract the wheel rearward.

As far as being nuts as concerned, I must be nuts for making the wheel axle the way that I did, using tiny #0-80 nuts.
It looks nice, but boy was it tedious. I used #0-80 screws, coming in from both forks, that meet in the center of the wheel, to form the axle. These screws actually have nuts on them, tightened against the inside the forks. A short piece of nylon pushrod sheating was installed over the screw threads, as I built the setup, to make a low friction axle. There is small clearance between this axle tubing and the wheel hub ID.

The way I assembled the axles was to install 1 of the 2 screws, and tighten the nut on the inside of the wheel caster fork. Then I loosely inserted the piece of nylon sheathing inside the wheel center, stretched open the fork slightly, and installed the wheel and its inner pushrod sheathing "axle bushing" onto the screw. Now I had to install the 2nd screw from the other side, get the nut inside the fork, and thread it tight. I did this by CA gluing the side of the nut onto the end of a piece of wire. Now I could get the nut into position, install the screw, and then snap off the piece of wire that was temporarily glued on. I had to perform this gluing operation several times, as the nut kept breaking off of the installation wire, as I was trying to get it into position.

All said, it was worth it, as the screw heads look nice, versus a piece of wire bent over at the ends. Too bad those little screws didn't have hex heads, as they would look really cool (scale) then. Maybe I'll have to glue fake nuts over them.

The setup is shown in the pic below. The wheel mounting pivot block is firmly attached, with its set screw tightening against a flat spot ground onto the mounting rod. The water seal can also be seen, which is a piece of fuel tubing that is stretched over the aluminum tube housing, which extends about 1/4" out of the fuse. A short length of the inner torque rod extends out of the aluminum tube housing, and the fuel tubing diameter is small enough to make a good seal against it.

For an example of a possible steering arm, 2 nuts and a servo control horn are shown. I may not use the servo horn for the steering arm, but it shows the principle. Irregardless, the arm/s will be a lot shorter. Now that I have a threaded steering shaft, I can mount pretty much anything I want onto the top of the steering arm.

BTW,
MikeF, saw you listed as a forum viewer here while I was logged on. Didn't know that you hung out here too.

Bill, you're right. The full scale didn't turn worth a darn with the rudder. Most steering on the ground was with brakes.
On a delivery flight, I taxied the full length of Norfolk International, in a strong cross wind.
By the time I got to the ramp, the fire trucks were already there. They saw the smoke from the wheels. The brakes would smoke if used too much.

Make the tailwheel strong, it takes a beating going up and down ramps into and out of the water.

Bill, you're right. The full scale didn't turn worth a darn with the rudder. Most steering on the ground was with brakes.
On a delivery flight, I taxied the full length of Norfolk International, in a strong cross wind.
By the time I got to the ramp, the fire trucks were already there. They saw the smoke from the wheels. The brakes would smoke if used too much.

Make the tailwheel strong, it takes a beating going up and down ramps into and out of the water.

The tailwheel assembly is definitely strong. The torque rod itself is .072" wire, and only a very short length is exposed. One good thing, is that between the wire torque rod that it mounts on, and the foam wheel, it has a lot of suspension as it is. If you drop the tail, it will bounce like a basketball for a few.
As for the brakes, I heard that they floored them when they could no longer keep the plane straight, and were going off the runway.

The Seabee:

Retracts
The retracts have been working for a while now, but I figured that I'd show a few pics. The first pic shows the test setup energized, with the gear down. In the second pic, I am holding the plane off the table, and the gear is retracted. If you look at the tailwheel, it is retracted by turning counter clockwise about 90 degrees on its mounting shaft. This is why the steering arm at the top is the only thing that can be seen in the left side view pic.

Steerable/Retractabe Tailwheel
I also have the tailwheel steering mechanism working well now. I need an updated pic, but the third pic below shows the principle. I have "cleaned up" the mechanism a bit, and it is now re-assembled with a pull cable. The cable exits a bit above where the mounting torque rod exits the fuse. The pull cable is inside nylon cable sheathing, and the sheathing is tied off at a high point in the fuse, before routing into the main cabin, so that it is above the water level and won't let water in. Gotta think about that stuff here.

To make the pull cable work, I fabricated a recoil spring, which is mounted under the steering arm at the top. Its in there, but is tough to see in the pic. One end of the spring is connected to the steering arm, and the other is locked against the tailwheel mounting block, and hooks around the torqe rod. This spring holds the wheel in a left turn, and the pull cable, attached to the steering servo in the cabin, will move in and out to activate the steering. At center postion, the spring does not require much force from the servo, so it will not overwork it. Even at full right turn, it is not very severe, as it does not require a strong spring force to hold the wheel to the default left turn position.

Tailwheel Recoil Spring
The recoil spring did take a while to fabricate. It has a bit more that 2 turns, wound from the points where it connects to the wheel mounting block and the steering arm. It took a while to get the spring rate correct, the end positions at the correct orientation relative to each other, and to make the coils neatly wound and tight together, as there is little space between the steering arm and the steering block. I could have moved the steering arm upward with another base nut, but I want the spring to be as concealed as possible.

Steering Arm
A bit of trivia is that the splined center of the steering arm, an HS81 servo control horn, fits just about perfectly on the steering shaft base nut. It would only move a degree or so, when set in place. This made it easy to get the steering spring in place and the steering arm in the correct position, before snugging it firmly with the top nut and lockwasher.

Updates, New stuff completed this evening:
The last 3 pics show the the tailwheel steering pull cable sheathing in place. It is tied off high in the fuse, before routing toward the cabin, so that it is above the water level. Looking closely, the pull string can be seen loosely threaded through the steering arm. Testing it by hand seems to work well. Also in the fourth pic below, is a small silver painted box that will slip over the torque rod and glue to the wheel pivot block, between the fuse and the tailwheel pivot block. This box was fabbed from thin plastic, and will simulate the I-beam type casting, that is part of the tailwheel pivot block on the full size plane. Note the arrow that points to the area that it will insert into, in the small detail picture of the full size plane's tailwheel.

Water Rudder
I stole my aluminum resting pad for my Monokote iron, to make the rudder from. I found something else to use for the Monokote iron stand.
A paper template of the rudder was first contact glued to the aluminum plane, and the reinforcing ribs were stamped into the rudder, using a hammer and a thin spatula with a strong blade. It worked well. In the last pic, the completed rudder can be seen against a full size example.

Rudder Linkage Plan
I plan to use the same pre-loaded spring setup for the water rudder, and set the spring tension so that the default postion is in the opposite direction. At the servo horn, these 2 springs would cancel each other out, when the water rudder and tailwheel are in center position.
In this case, the opposite side of the servo horn would be used for the water rudder cable connection, and the logic would be reversed, with the rudder set to at "normally right". The servo would "let out" the cable, and the spring would move the rudder.

Finished the water rudder setup today. I ended up using a Sullivan Gold Cable, which is capable of driving the rudder in both directions, versus the lighter pull-only idea, with a one-directional spring. I thought about using the light pull cable used in pull-pull setups, and then ruled it out, since I don't want something that has a chance of breaking, where I can't get in there to fix it. I still mounted the spring on the rudder linkage in the fuse, so that it would cancel the force of the one-directional spring on the tailwheel, to remove the load from the rudder servo.

The first pic shows the aluminum tubing that will slide over the rudder. The tubing has a slit through most of its length, that will slide over the rudder. Two slits about 1/4" deep were cut in the top of the rudder, for the portion of the aluminum tubing that was not slit, to slide into.
The rudder steering shaft has a notch filed into it, that makes a "half-shaft" of the portion which the rudder will mount against. This part slides into the aluminum tube at the top of the rudder, and has an #0-80 screw and nut to secure it in place. It can be seen in the pic, protruding through the fuse.

The aluminum tube is secured to the rudder with thick CA, after it is slid in place. The second pic shows the gluing procedure. First, a wire was inserted to block the mounting hole, in the tab that was cut into the top of the rudder. This is done so that when the CA is injected in the fastening hole of the aluminum tubing, it will only fill on one side of the rudder. An arrow points to this hole, in the pic. The other side has to be kept open, for the "half shaft" portion of the steering shaft to slide into.

The third pic shows the mounting hole being re-drilled, since one side of the alum tube is filled with CA, and needs to have the mounting hole opened again. The last step is to inject CA into the bottom openings of the tubing, on either side of the rudder, so that the tubing does not separate from it, as the tube was slit to slide over the rudder. I also scuffed the rudder surface under the sandpaper, so that the CA would grip. Only a small amount of thick CA was used, so that it would not run toward the other end, and clog the area that needs to slide over the steering shaft mount.

In the last pic, the rudder is in place, with the mounting screw partially inserted. Not in the pic, is a servo control horn that is attached to the top of the steering shaft, used for the cable attachment.

Finally just about finished with the tailwheel/water rudder area of this plane. In the first pic, the completed linkage for the water rudder can be seen. I attached a servo horn to the top of the rudder shaft, for the linkage point, which will also be used a the take-off point for the air rudder linkage, eliminating the need for another pushrod that would need to route all the way to the cabin. This also saves weight, as this plane has a tendency to get tail heavy, which is why I used a nylon Dubro linkage connector, instead of the heavier Sullivan Gold connectors, used to drive the retract linkage.

One major difference between this build, and the 1977 Model Airlane News plan build which I am referencing, is that my tailboom is scale. The existing MAN plan has a simplified boom, where the bottom hull corners are rounded, and the smooth "step" in the boom of the real airplane, at the tailwheel, is squared off. They did this for simplicity. I like the smooth blended transition of the full-scale Seabee, in this area of the boom, and also having the correct shape for the formers. I think squaring this transition really hacks this plane, since it has such nice flowing curves. It does add more work, however, to make it scale.

The most difficult part of making a scale boom is the smooth "step" transition at the tailwheel. It would be tedious to attempt to frame this curved area with formers and stringers and then strip plank, so I sculpted filler parts for this area, using soft, light balsa (see second pic). The sheeting will blend into these filler pieces, overlapping it at the edges of these parts.

Have you given any thought to the spray rails?
On the two Sea Bees I flew, they were both modified with the wide spray rails, to keep water off the prop.

Also any thought of a variable pitch prop, with reverse?

The Sea Bee was the first airplane I flew that had reverse.
It was very helpfull in the water.

It also freaked a few linemen out to see the monster back up into a parking spot on land.

Newcomer, I like your work too. If you haven't recognized me, I'm the guy that's into the Luft '46 stuff like you build, at that other place.

The variable prop would be cool. A few $$ too, but cool. I guess there are some stronger ones out there, than the light duty ones that I've seen for foamies. I wonder if folks have used reversing rc car/boat variable speed controllers, and reversed the rotation? The prop is not as good that way, but will still reverse thrust.
I am adding lights though. Already have the tail light wired in the rudder.

If I do the spray rails, I'd probably want to build them into the structure before I sheet it, so they won't break off easily. The idea would be to have them notched to insert into the cabin, and glue off a bit inside the walls, so they can't just "snap" off the outer hull. I probably won't add them, but if I do, I'll probably do it as described. Maybe the model will not spray as much as the full size, since the surface tension and other properties of water will not be "scaled" like the model.

I was working on the front hull formers a bit last night. I shaped the bottoms to have a curve, like the full-scale plane. This curved front hull will help displace water when it first gets going, before the hull gets out of the water. It also looks better and more scale-like this way. I'll have to look again at the video links I posted before, and see how the water displaces with that plane. Its the same size as mine, and his hull panels are completely flat, with no curve in front.

Bill, Here's a repost of exerpts from the factory manual from the other site.
Let me know if there is any other parts of the owner's manual you would like to see.

When I built the front dash support in my plane, I wasn't paying attention as much as I should have been, in the sense that it goes all the way across. I should have put it in lower. I still may mod it. I noticed that there seems to be an old version of the instrument panel, that looks different, as it goes all the way across.http://www.stinsonflyer.com/prop/irc3-01.jpg
I may do mine that way, since it would be easier to do now. I still may go with the newer version that you showed, as I could still incorporate it into the plane, since the top of it is higher than the window line, where my support is located.

Build progress
I added the front hull section using basswood sheet. I thought about just filling the area with soft balsa and shaping, but the sheeting is actually easier in the sense that you get the right shape with little work, if its done right. I added a few strips of sqare stock wood to the hull formers, to provide a good gluing surface the the lower most portion of these sheets. This part was glued first, and then the sheets were dampened and stretched along the hull curves and CA glued in place. By having the sheets firmly glued to the former first, I was able to stretch the correct compound curves into them. They actually curve in 2 directions, along with the bottom hull profile, and are concave to displace water. Good thing that we have activator, to speed these bonds up.

Before the sheets were added, the curved frames were added, that are seen in the first pic. I've found that if you soak the 1/8" spruce square stock, you can eventually shape it like a soft pretzel. In the picture of the full-size Seabee below the model, this curved seam in the hull panels can be seen. The idea here is to get the hull as close to scale as possible. The models I've seen so far have not included all the curves to scale accuraccy. The remainder of the front area will probably be sculped from balsa.

On the scale, everything so far is 13oz, which is actually better than I thought it would be, at this point. The lightening holes do not remove as much weight as expected, but the main point was to keep the tail light, which was also one of the reasons not to sheet the tail feathers. The tail lightening is important, since every gram of excess tailweight requires about 2 grams in the nose, to maintain the CG setting.

The Sea Bee landing gear rotated rearward, there was no well for the gear.
The picture shows a wheel well.
Also the Sea Bee had the wing strut ahead of the gear. There is no strut in that picture, I vote it's a Riviera.http://www.aeromods.com/riviera/

Also, the Sea Bee had a third door in the front for docking, if the panel went across as depicted, you couldn't use the door.

You build looks good, and I bet the lightening holes pay off dividens, it's easier to remove one gram of weight from one hundred parts than one hundred grams from one part.

The Sea Bee landing gear rotated rearward, there was no well for the gear.
The picture shows a wheel well.
Also the Sea Bee had the wing strut ahead of the gear. There is no strut in that picture, I vote it's a Riviera.http://www.aeromods.com/riviera/

Also, the Sea Bee had a third door in the front for docking, if the panel went across as depicted, you couldn't use the door.

You build looks good, and I bet the lightening holes pay off dividens, it's easier to remove one gram of weight from one hundred parts than one hundred grams from one part.

Paul

Guess I didn't look that closely. I looked at the link for a second or 2, and then saved it. I guess I'll be modelling the standard instrument panel then. Should still look pretty good, as the top portion with the rounded corners will rise above my existing dash support, and the front of it will be much larger than the small cross tie that goes across the cabin in the same location. I could take out my dash reinforcements and move them down, but I prefer to keep them where they are.

On the lightening, I'm starting a new principle of removing weight from most ALL parts that I can. I may be minor, but weight is weight, and it all adds up. I heard about a redesign of one of the Mazda 262 prototypes around 1990. To lighten the car, the project manager specified a 10% weight reduction of all the parts. Realistically, I'm sure it wasn't every part, but the idea still stands. Keep every part as light as possible. Remember, it has to defy gravity.

Seabee Tailboom Trussing and Stringing
Most of the tail boom stringers are in place now. Looking carfully at the pic, trusswork can be seen also. The trusswork basically makes it like a bridge, in design. Fuse formers offer little strength longitudinally. One poor solution would be to make the formers out of heavy ply. A much more efficient soulution is to add lightweight trusswork. Another benefit is that stress concentrations can be relocated. Notice the longer truss braces at the beginning of the boom, coming off of the cabin. They tie in to the center keel aft of the point where the boom connects to the fuse. This disributes the stress concentration at the cabin-boom joint, where the stresses are the highest and it is most likely to break.
To get an idea of the potential strength added by trussing, look at the MIT students that put incredible loads on model bridges made of balsa.

The plane will be sheeted with 1/32" sheeting, which was one of the first decisions made on this plane. Using 1/16" sheeting would make it a tank! I'd rather add a few more stringers to support the thinner sheeting and still come out lighter, than to get away with adding fewer stringers by using thicker sheeting. 1/32" sheeting is a lot easier to work with also. I'm not a strip planker. I like working with larger sheets, and am a big fan of sheeting. I sheet everything. It adds challenge to building micro flyers too. I've already worked out most of the sheeting scheme. Shouldn't be too bad.

Hitting the CG looks right on target at this point, now that I have most of the tail boom weight in place so that I can check it. I taped the tail feathers in place and put a TP 3s-2100PL in front, and I am actually about 2" in front of where the CG needs to be. When the motor is installed later, toward the rear of the wing, it should then be close. While I realize that the CG can still change a bit as the build progresses, I'm at the point now where I believe that I will not need much ballast, if any, to mount the motor on the rear half of the wing. I want to avoid using a driveshaft, so that the motor can be mounted on the front of the wing, but will still do so, if it saves from needing substantial nose ballast.

Are you planning to give the structure a coat of sealant of some kind, before sheeting?
I used to fly a lot of models off water, the planes would magically gain weight as the day progressed.

Covering with 1/32 sheet, my hats off to you.
I can't work with that thin stuff anymore.
I've had a lot of nerve damage in my hands, and now I'm always breaking pieces off my planes before they are finished, and that's with the heavy stuff.

Why does it seem on this forum that so few people actually leave comments?
I think a lot of people are reading these threads, but they just don't ask or comment.
Just wondering why, this plane is so different that I thought people would be flooding you with questions.

Are you planning to give the structure a coat of sealant of some kind, before sheeting?
I used to fly a lot of models off water, the planes would magically gain weight as the day progressed.

Covering with 1/32 sheet, my hats off to you.
I can't work with that thin stuff anymore.
I've had a lot of nerve damage in my hands, and now I'm always breaking pieces off my planes before they are finished, and that's with the heavy stuff.

Why does it seem on this forum that so few people actually leave comments?I think a lot of people are reading these threads, but they just don't ask or comment.
Just wondering why, this plane is so different that I thought people would be flooding you with questions.

I'm sure watching it! I'm amazed at the talent and skill level on this. I can't wait to see it fly. Bill, you can't wait two years to maiden it though.

Hi Tom, he's doing a fantastic job on a very unusual and difficult plane.

The build has so many departures from normal planes that I was just wondering why there has been so few questions.
I know I have a million questions on this build, and I'm seeing more as he works.
I just feel guilty asking all the questions.

Watching also. No questions at this time but I do echo those comments regarding some kind of internal waterproofing. I lost a water rudder on a Seamaster last year due to covering coming loose and becoming water soaked.

Presently I am building a Cessna 195 kit (will have floats) and waterproofed all internal parts I could.

What this thread teaches - I hope - is how light you can build a strong structure. Something I am still learning as I tend to make parts stronger than necessary.
Joe

Grasshopper, I will want to fly this plane sooner than that, but the problem is that it may take 2 years to finish. A lot of details on this plane that I'm not use to doing on the standard issue warbirds. Construction is just a little different too.

I was just staring at a can of Balsaloc last night, and wondering if it is a waterproofer. I definitely want some type of waterproofing on at least the lower hull wood. Considering that I actually use water to soak hardwood stringers and basswood and ply sheeting so that it can be formed like a soft pretzel, I think it would be a good thing to waterproof them.

What are folks using for waterproofing wood?
Can sheeting still be glued to the wood afterwards?

Joe, I really could use some better pics, but the trussed boom structure is probably the best example of using lightweight bracing. A structure like this can be trussed, like bridge construction. To gain the same strength without them, the boom formers would have to be made from much heavier wood. I tend to make stuff much stronger than necessary too. What I'm trying to get away from, is to make one section of a part stronger than needed, while another section is still the weakpoint. In other words, inefficient.

I also thought about the potential of losing parts. My tailwheel assembly is spring loaded with a pull cable looped through the steering arm. I ain't losin' that part! Way too many hours into the little sucker for that to happen. The water rudder has a small set bolt, not screw, but bolt going through it, and the top of the steering shaft is permanently welded (mrg part) to the shaft. Same goes for that part, I'd cry if I lost it.

Another thing I started paying attention to here, is reinforcing long stringers. Nothing is worse than breaking one, after your plane is sheeted and finished. If you look at how they fail, its usually in the center, especially when the plane is handled, and a spot is gripped too hard. The wood fails when the far side of the center exceeds the tension and bending limit of the wood, and does not fail in shear. Balsa is not good in tension, in the cross grain direction. What's not as obvious, is that is you can stiffen the stringer to STOP it from bending, then it will not fail nearly as soon. I've found that if you laminate a second stringer of only about 1/3 the length of the stringer section, in the center and on the inside, that the strength gain is substantial. Laminating a full length stringer to an existing stringer is just dead weight, since the section that usually fails is the inner face of the very center, which fails in tension and bending. Another thing I found is that it is the lamination layer of the CA that really provides much of this added tensile strength, just like in the resin engineered beams. The reinforcer added to the center of a stringer does not need to be as thick as the original stringer, for a large gain in strength.

While that may seem like quite a dissertation on adding a small reinforcement patch and a point load in the center of a beam, its something I will probably be looking at in the future. Using the idea, a plane could be built with fewer formers and longer spans of stringers in between. The weight of the short splices added to the stringers is less that the reduced former count, and the strength gain is considerable.

New progress is the elevator servo and pushrod are in place. I made an adapter mount for the elevator servo, so that I can remove it and install a larger servo if I choose to, as a drop in replacement.
Bill